Acceleration of anaerobic reactions by conductive carbon nanomaterials

Abstract

Anaerobic processes are environmentally friendly solutions for the decontamination of a wide range of recalcitrant compounds, while generating energy through the production of methane, a renewable energy source. The rates of anaerobic biotransformations are often slow, but the amendment with carbon-based conductive materials (CBCM) has been reported to accelerate the microbial conversions. For example, methane production from organic compounds could be accelerated in the presence of CBCM, which has been often justified by the occurrence of direct interspecies electron transfer (DIET), between anaerobic bacteria and methanogens, over the typical electron exchange via hydrogen or formate. However, in these studies the effect of conductive materials towards individual microbial species was never determined and therefore it is difficult to conclude whether it influences the entire microbial community and changes the electron transfer mechanism between distinct microbial groups, or whether it only stimulates the activity of specific groups of microorganisms. In our laboratory, we have been investigating the effect of CBCM in two main research areas: in the anaerobic biodegradation of organic pollutants, and in the activity of pure cultures of methanogens and in syntrophic co-cultures.